Make lwjgl not a runtime dependency

[Bixilon]

Currently lwjgl is not only a build dependency, it is also required at runtime. I noticed that in #35, everybody who pulls it from there is atm requried to have lwjgl:

      <groupId>org.lwjgl</groupId>
      <artifactId>lwjgl</artifactId>
      <version>3.3.2</version>
      <classifier>natives-linux</classifier>
      <scope>runtime</scope>
    </dependency>

(in my case it even forces linux natives on any platform)

This probably requires changes in the gradle plugin https://github.com/LWJGL/lwjgl3-gradle.

Additionally there are a lot of unused lwjgl imports and all references to it need to be removed and outsorced to maybe kool? Then it could be removed totally here.